1. Field of the Invention
The disclosure relates to a signal processing apparatus and method.
2. Description of the Prior Art
In the voice command function, the core task is to recognize the audio signal recorded before executing a command, and after the command is recognized determine the corresponding action to be taken by a system (e.g., a computer system) based on the recognized command. For example, when the system obtains a command of opening the web browser through the speech recognition, the system will open the web browser correspondingly. In another case, if the system is in the power saving mode (e.g., the sleeping status), and a wake-up command of waking up the system is derived from the speech recognition, the system will leave the power saving mode (e.g., the sleeping status) and return to the normal mode (e.g., the normal operation status).
In order to perform the system speech recognition without missing any key voice signal, the system may keep receiving the audio signal by a microphone, and keep recognizing the digitalized signals recorded. However, the process of receiving the audio signal often makes the recorded signal to be recognized contain too many none-voice durations.
The task of speech recognition is generally performed by software programs. If the audio signal received by the microphone is continuously sent to the speech recognition system for calculation, but no key voice signal occurs in the duration of receiving the audio signals, this will lead to unnecessary waste of power, and thus fail to follow the power saving trend. Consequently, if the speech recognition system is located in a mobile device, the battery life will be shortened.
Traditionally, to avoid the additional power waste due to keeping performing the speech recognition or save the temporary storage space needed before speech recognition starts, the user may be required to transmit/trigger a voice starting command in a manual manner (for example, key pressing) before using the speech recognition, and transmit a voice ending command in a manual manner (for example, key pressing) after entering the audio input. Therefore, the speech recognition system only needs to recognize the audio signal present in the duration between the voice starting command and the voice ending command.
However, because the user needs to enable and disable the speech recognition manually, the user therefore needs to touch the system key by himself/herself to enable and disable the speech recognition well. Hence, such a control mechanism of speech recognition is not very convenient for users. Moreover, when the aforementioned speech recognition mechanism is applied to the voice wake-up function of the system, the voice starting command and the voice ending command may not be triggered because the user can not touch the key of the system directly for some design models. Thus, the only way to provide the voice wake-up function is to keep receiving audio signal, recording the audio signal, and performing the speech recognition. This mechanism for voice wake-up function fails to achieve the purpose of saving power.